A rotating disk electrode (RDE) is one of a number of hydrodynamic voltammetric techniques that is widely used for the study of kinetic and mechanistic electrochemical processes at solid electrodes as well as for electroanalytical applications. RDEs are used in a variety of electrochemical measurement applications, including, for example, battery characterization, measurements of electrocatalyst activity such as for example electrocatalysts for Proton Exchange Membrane Fuel Cells, corrosion studies and electroplating and electrocodeposition studies. The RDE technique is commonly used for the electroanalysis of trace metal components such as mercury and organic additives in plating baths. An electrochemical reaction is a reaction involving the transfer of charge as a part of a chemical reaction. Typical electrochemical reactions in corrosion are metal dissolution and oxygen reduction. The RDE controls the transport regime of electroactive species toward the electrode. Rotating disk electrodes are typically constructed from a disk of electrode material (e.g., gold, glassy carbon, or platinum) imbedded in a rod of insulating material (e.g., Teflon). The electrode is attached to a motor and rotated at a certain speed. The movement of rotation leads to a well-defined laminar liquidus electrolyte flow pattern that can be predicted mathematically. The rotating device acts as a pump, pulling the liquidus electrolyte toward it and then throwing the electrolyte outward.
Conventional rotating disk electrodes are temperature limited, due to their construction materials and structures. For example, conventional RDEs use Teflon or other polymers as electrical insulating or sealing materials, which limit the processing temperature of the RDE to less than 300° C. Furthermore, polymeric materials typically have a thermal expansion coefficient (TEC), which is orders of magnitude larger than typical RDE core materials (e.g., graphite, glassy carbon), resulting in limited temperature ranges for measurement applications.
In preparing rotating disk electrodes for certain applications, it is desired to subject the electrode or electrode materials to high processing temperature (e.g., greater than 300° C.) or to a specific processing environment. It may also be desired to carry out measurements at elevated temperature (e.g., greater than 80° C.). Furthermore, for many applications it is desired that the rotating disk electrodes are detachable from a mechanical shaft which couples the electrode to a drive motor during testing, so that only the RDE is subject to specific processing or treatment at stringent environments. It is further desired to have a RDE structure that allows for a four wire connection near the RDE tip to reduce electrical noise originated from rotational coupling of electric contacts.